how to fix P0303 code in Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Sub-steps:
  • Remove the engine cover if applicable using a socket set.
  • Disconnect the ignition coil connector and remove the ignition coil from cylinder 3 using the socket set.
  • Unscrew and remove the spark plug from cylinder 3 using a spark plug socket.
  • Inspect the spark plug for signs of wear or damage; replace with a new spark plug if necessary (recommended gap: 0.043 inches).
  • Reinstall the spark plug and torque to the manufacturer’s specifications (typically around 13 lb-ft).
  • Reinstall the ignition coil and reconnect the connector.

3. Check and Replace Ignition Coil

• Sub-steps:
  • If the spark plug is in good condition, test the ignition coil using a multimeter (check resistance according to specifications).
  • If the coil is faulty, remove it and replace it with a new ignition coil.
  • Reconnect the ignition coil connector securely.

4. Inspect and Clean Fuel Injector

• Sub-steps:
  • Remove the fuel rail if necessary to access the fuel injector for cylinder 3.
  • Disconnect the fuel injector connector.
  • Remove the fuel injector from its seat and inspect it for clogs or damage.
  • Clean the injector using a fuel injector cleaner or replace with a new injector if needed.
  • Reinstall the fuel injector and reconnect the fuel rail and injector connector.

5. Perform Compression Test

• Sub-steps:
  • Remove the spark plug from cylinder 3.
  • Insert the compression tester into the spark plug hole.
  • Crank the engine and record the compression readings.
  • If compression is low, further diagnosis may be needed for internal engine repairs.